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Outlook keeps on freezing for past 2 days

Keith Miller 25 Reputation points
2026-01-16T21:11:27.3233333+00:00

I am having significant issues with my Outlook Classic freezing. this has happened fdor the past 2 hours and I am spending hours trying to send an email. Please help.

Microsoft 365 and Office | Other

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  1. nobuko c 123.2K Reputation points Independent Advisor
    2026-01-16T21:57:55.2466667+00:00

    Hello,

    It appears that a serious issue has recently been occurring in environments where the security patch KB5074109 has been applied, specifically affecting Outlook Classic.

    If you see the security patch KB5074109 listed under Windows Settings > Windows Update > Update history, please uninstall it and restart your PC.

    After that, pause updates from Windows Settings > Windows Update and check whether the issue persists.

    Additionally, we have confirmed that KB5074109 can cause sleep and hibernation problems in certain environments.

    4 people found this answer helpful.

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  1. Q&A Assist
    2026-01-16T21:11:36.15+00:00
    AI generated content. This question contains an answer created with AI from Q&A Assist. Learn more

    If Outlook is freezing, it could be due to several reasons. Here are some troubleshooting steps you can take to resolve the issue:

    1. Check for Updates: Ensure that you have the latest updates installed for Outlook. Not having the latest updates can cause performance issues.
    2. Close Other Processes: Sometimes, Outlook can freeze if it is in use by another process. Make sure no other applications are interfering with it.
    3. Disable Add-ins: A previously installed add-in might be causing the issue. Try disabling any add-ins to see if that resolves the freezing.
    4. Reduce Mailbox Size: If your mailboxes are too large, it can lead to performance issues. Consider archiving old emails or cleaning up your mailbox.
    5. Repair Microsoft 365 Programs: You may need to repair your Microsoft 365 installation if there are corrupted files.
    6. Check Antivirus Software: Outdated antivirus software or conflicts with Outlook can cause freezing. Ensure your antivirus is up-to-date and consider disabling its integration with Outlook temporarily.
    7. Create a New Profile: If your user profile has become corrupted, creating a new Outlook profile may resolve the issue. You can do this through the Control Panel under Mail settings.
    8. Run the Classic Outlook Advanced Diagnostics Troubleshooter: This tool can help identify and fix issues automatically. Make sure you are using the same Windows device that classic Outlook is installed on.

    If the problem persists after trying these steps, you may want to consult further resources or support from Microsoft.

    References:

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